Correlation Between Rotation of the Femoral Component and Early Passive Flexion After Total Knee Arthroplasty

Background: The factors influencing postoperative range of motion after total knee arthroplasty have so far not been fully determined. Early postoperative flexion of 90 degrees is an important criterion for discharge, and therefore desirable. We analysed the possible association between the rotation of the femoral component and early postoperative flexion. Materials and Methods: The early passive postoperative range of motion on the sixth postoperative day after primary total knee replacement with the LCS prosthesis was investigated retrospectively. 42 patients treated in 2008 were analysed. Only patients with osteoarthritis and a preoperative range of motion of more than 90 degrees were included. The same surgical technique was used for all patients and they all received the same postoperative treatment. We used Kanekasu's technique for the final radiographs. With this technique it was possible to ascertain the rotation of the femoral component after total knee arthroplasty easily and with a low level of radiation. Results: There was a significant correlation between the early passive postoperative range of motion and the rotation of the femoral component, but no significant correlation was found between the preoperative range of flexion and the early passive postoperative range of motion. Conclusion: This study revealed a significant correlation between rotation of the femoral component and early passive postoperative range of motion after total knee arthroplasty.